Which element does the electron configuration 1s22s22p2 represent? B C N K

The electron configuration is 1s2 2s2 2p2, then the number of electrons is 2 + 2 + 2 = 6. The number of electrons equals the number of protons and this is the atomic number. So, the atomic number of the element is 6. In a periodic table you can find that the element with atomic number 6 is carbon. So the answer is C.